This invention relates to a supervisory control system for an electric power system.
An electric power system comprises transmission lines and electric power houses situated at discrete locations. An "electric power house" as employed herein may be a power station, a substation, a switching station, a combination of such stations, or the like and comprises "electric power apparatus" which may be a dynamo, a transformer, a circuit breaker, a line switch, a voltage regulator, a phase modifier, and/or the like, among which the first two are called herein "primary power apparatus" and the rest are called "secondary power apparatus". In some cases, loads may be substituted for an electric power house.
A supervisory control system for an electric power system comprises a plurality of detecting devices associated with the power system at various points for detecting instantaneous analog data, such as voltages and currents, and for detecting the inherently stationary data representative of the states, of the power apparatus. The supervisory control system further comprises protection and supervisory control equipment for processing the above-mentioned data to carry out protection and other supervisory control of the power system and communication equipment for transmitting the processed data between a local electric power house and adjacent electric power houses. The protection and supervisory control equipment of the conventional supervisory control system makes use of the analog data in comparing the voltage and current data with the standard voltage and current, in deriving the sums of the currents in different wires, in discriminating the phases of the voltages and currents, in calculating the effective power, and in otherwise processing the data.
As the power system becomes greater in scale more intricate in construction, defects of the conventional supervisory control system have grown more serious and notable. As will later be described in detail with reference to the accompanying drawings, such defects reside in the necessity of using high-power outputs for the detecting devices, the complicated structures of the current transformers, the inevitable error in the instantaneous current data, bulk of the cables for transmitting the detected high-power outputs to the protection and supervisory control equipment, the limited reliability of the analog data processing, the poor performance of supervisory control systems for wide areas, the meager versatility of supervisory control systems, and so forth.